feat(r): Add async infrastructure for specific methods #279

Job	Run time
check (macOS, adbcdrivermanager) / r-check	1m 48s
check (macOS, adbcflightsql) / r-check	1m 45s
check (macOS, adbcpostgresql) / r-check	1m 38s
check (macOS, adbcsqlite) / r-check	1m 40s
check (macOS, adbcsnowflake) / r-check	1m 53s
check (ubuntu, adbcdrivermanager) / r-check	1m 50s
check (ubuntu, adbcflightsql) / r-check	2m 5s
check (ubuntu, adbcpostgresql) / r-check	1m 53s
check (ubuntu, adbcsnowflake) / r-check	1m 51s
check (windows, adbcdrivermanager) / r-check	1m 55s
check (ubuntu, adbcsqlite) / r-check	1m 50s
check (windows, adbcpostgresql) / r-check	1m 43s
check (windows, adbcflightsql) / r-check	1m 55s
check (windows, adbcsnowflake) / r-check	1m 52s
check (windows, adbcsqlite) / r-check	1m 50s
	27m 28s

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